1. Field of the Invention
This invention relates generally to sawdust collecting apparatus and, more specifically, to a sawdust collecting bag having a screened vent portion between the inlet to the bag and the bottom of the bag. The herein disclosed bag can be used as a receptacle for the flow from a vacuum-collecting system, or may be advantageously used alone to collect sawdust transported by a combination of gravity and the air currents generated by the rotation of the saw blade.
2. Description of the Prior Art
In the past, saws have been extensively utilized for altering the dimensions of objects by cutting away portions of the object. That cutting operation is accomplished by cutting individual chips from the object with the sequential moving teeth of a saw to form a kerf, or saw cut. Once cut from the object, the chips are removed from the cutting situs by the continued movement of the sawblade. The rotation of the saw blade generates air currents which, in combination with gravity, and in the case of a rotary saw the centrifugal force generated by the rotary motion of the blade, tend to distribute the accumulation of chips, or sawdust, generally about in a manner necessitating a clean-up after the use of the saw, at least where the use of the saw is in an area which is preferably maintained in a clean condition.
Various devices have been developed to collect dust and chips generated by a cutting or grinding operation. A typical approach is shown by U.S. Pat. No. 1,267,171, issued to H. L. Bee for a dust collector on May 21, 1918. The Bee patent features the use of the dust collecting apparatus for a grinding or buffing device, which incorporates a vacuum generator whose inlet is coupled to a hood generally surrounding the dust generating portion of the device, and whose outlet is provided with a bag so that the flow generated by the rotary vacuum pump will be filtered through the bag.
Another typical device of the prior art is shown by U.S. Pat. No. 2,839,102, issued to G. S. Kido on June 17, 1958. The Kido patent teaches the use of a table level hood to permit a vacuum source to collect sawdust generated by a radial arm saw. Similarly U.S. Pat. No. 3,274,892, issued to E. A. Carsey on Sept. 27, 1966, teaches the use of a hood assembly mounted above the table of a metal working machine to permit dust and metal chips to be collected by a vacuum source without interfering with the operation of the metal working machine. Other suction operated dust collecting devices designed to be operated above the working surface of a saw are shown respectively by U.S. Pat. No. 3,322,169, issued May 30, 1967 to L. E. Hillard, and by U.S. Pat. No. 3,945,281, issued Mar. 23, 1976 to L. D. Kreitz. A particular type of below-the-table mounted sawdust collecting hood, for use in conjunction with a vacuum source, is shown by U.S. Pat. No. 4,063,478, issued on Dec. 20, 1977 to H. Stuy. Each of the devices of the prior art required a powered vacuum source to effectively function as a sawdust collector. A need existed for a device to permit a collection of a substantial portion of the dust and chips generated by a saw, grinder or other similar unit, which device did not require an expensive vacuum system.